This invention relates to piezoelectric ignition devices for gas appliances such as propane lanterns and gas barbecue grills. More particularly, the invention relates to a piezoelectric ignition device which is operated by the on-off control knob of the gas valve of the appliance.
Piezoelectric ignition devices are commonly used for igniting propane lanterns, barbecue grills, etc. A piezoelectric ignition device generally includes a piezoelectric crystal, an impact hammer for striking the crystal, and an electrode for conducting voltage from the crystal to the point of ignition. The outer end of the electrode is spaced from a grounded conductor. The piezoelectric crystal generates a voltage when it is impacted by the hammer, and propane or other fuel is ignited when the piezoelectric electrode arcs to ground.
U.S. Pat. No. 4,691,136 describes a typical piezoelectric ignition device for a gas appliance. The piezoelectric ignition device described in the patent is actuated by a cam knob which is rotatably mounted on the appliance. Rotation of the cam knob moves a spring-loaded hammer away from the piezoelectric crystal and then releases the hammer. The gas valve of the appliance is operated by a separate control knob, and rotation of the cam knob must be coordinated with rotation of the control knob.
I am aware of a Japanese gas stove which uses a control knob attached to a butane regulator to turn the gas on and to activate a piezoelectric ignitor when the regulator reaches the full open position. The knob engages a trip mechanism which moves tangentially with respect to the knob to actuate the ignitor.